I use Principle quite a bit and it certainly has its strengths (and weaknesses), but I see two key features that are pretty much necessary to make this product relevant in 2020+.
The Mirror app also for Android, and a link generated to send to test participants. I personally have an iPhone, but limiting test screening to just iOS is not realistic depending on the project especially. Nor is the process of getting the test artifact(s) to them.
Who here does high-fidelity usability testing? Have you explored other tools? Proto.io?
Steps to reproduce the behavior:
Screenshots/Sketch File/Principle file: (if applicable)